<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" src="../../js/vue.js"></script>
</head>
<body>

<div id="app">
    <input type="text" v-model="username">
    <p>Hello {{username}}</p>
</div>
</body>
</html>
<script>
    const vm = new Vue({ //配置对象
        el: '#app', //element选择器
        data: { //数据(model)
            username: ''
        }
    })
</script>
<!--mvvm
m：model 模型data
view；模版页面
vm：模版视图
-->
